A substrate, such as a carrier wafer, is often used to support a semiconductor device, such as a semiconductor wafer that includes a plurality of dies, to permit further processing on the semiconductor device. For example, a semiconductor device may include a plurality of structures, such as pads, pillars, and/or vias, on a first or front side of the device. During the processing of the semiconductor device, the thickness of the semiconductor device may need to be reduced. Various processes, such as, but not limited to, chemical mechanical planarization, grinding, and/or dry etching, may be applied to the back or second side of the semiconductor device to remove material from the semiconductor device. For example, the thickness of the semiconductor device may be reduced from 775 microns down to 70 microns using various processes known by one of ordinary skill in the art.
Presently, a semiconductor device, such as a semiconductor wafer, may be temporarily bonded to a substrate, such as a carrier wafer, with a temporary adhesive to form a temporary semiconductor device assembly. For example, the first or front side of the semiconductor wafer may be bonded to a carrier wafer with a temporary adhesive that is spin coated onto the carrier wafer. After completing the processing on the second or back side of the semiconductor wafer, the semiconductor wafer is removed from the carrier wafer. Typically, the semiconductor wafer is removed or debonded from the carrier wafer by thermal/mechanical sliding. In other words, the temporary semiconductor device assembly is heated and force is applied to slide the semiconductor wafer off the carrier wafer. The present process of removing the semiconductor wafer from the carrier wafer may result in, among other things, die cracking and/or pillar smearing. Further, the present process may result in breakage of the semiconductor wafer itself. The edges of the semiconductor wafer may break, crack, or chip during the removal/debonding process.
The term “temporary adhesive,” as used herein, means an adhesive and/or epoxy that has a glass transition temperature, Tg, of 150 degrees Celsius or less. The Tg is the temperature at which the adhesive and/or epoxy transitions from a hard, glassy material to a soft, rubbery material. An adhesive is used to temporarily bond the semiconductor device to the substrate. The semiconductor device is temporarily bonded to the substrate as the semiconductor device may be removed from the substrate after the requisite processing is completed. In order to ensure that the semiconductor device may be removed from the substrate, a temporary adhesive is often used to temporarily bond the semiconductor device to the substrate rather than a stronger more permanent adhesive. However, the temperature during some of the processes applied to the semiconductor device and substrate assembly often may exceed the Tg of the adhesive used to temporarily bond the semiconductor device to the substrate, whether a “temporary” adhesive is used or not, which may cause the adhesive to move and/or squeeze out from between the semiconductor device and the substrate assembly. The movement of the adhesive may result in the surfaces of the semiconductor device assembly being non-planar, which may be problematic as would be appreciated by one of ordinary skill in the art.
Additional drawbacks and disadvantages may exist.
While the disclosure is susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and will be described in detail herein. However, it should be understood that the disclosure is not intended to be limited to the particular forms disclosed. Rather, the intention is to cover all modifications, equivalents and alternatives falling within the scope of the disclosure as defined by the appended claims.